
// setTimeout(function () {
//     var a = 'hello'
//     setTimeout(function () {
//         var b = ' lagou'
//         setTimeout(function () {
//             var c = ' I ❤️ U'
//             console.log(a + b + c)
//         }, 10)
//     }, 10)
// }, 10)

Promise.resolve('hello').then(value => `${value} lagou`).then(value => console.log(`${value} I ❤️ U`))

new Promise(resolve => resolve('hello')).then(value => {
    return `${value} lagou`
}).then(value => {
    console.log(`${value} I ❤️ U`)
})